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PV: Plenarvorträge

PV VI

PV VI: Plenarvortrag

Dienstag, 27. März 2007, 08:30–09:15, H1

Climate Change 2007: The Physical Science Basis — •Peter Lemke — Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, D-27515 Bremerhaven

Climate variations are a result of complex interactions between the atmosphere, the ocean, the cryosphere and the land surface including the marine and terrestrial biosphere. Until 250 years ago, the interference of man was negligible, and climate variations were a product of natural processes and interactions alone. Since the beginning of industrialisation the composition of the atmosphere, especially the concentrations of greenhouse gases like carbon dioxide and methane, have significantly increased. In addition, the character of the land surface has been largely modified through land-use and land-cover change through human activities. Part of the observed global warming during the past 100 years is attributed to these anthropogenic impacts.

In 1988 when the problem of potential anthropogenic effects on the climate system was recognised, the Intergovernmental Panel of Climate Change (IPCC) was established by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP). The Fourth IPCC Assessment Report is currently in preparation by three working groups and will be published in 2007. Working Group I deals with "The Physical Science Basis", Working Group II discusses "Impacts, Adaptation and Vulnerability", and Working Group III addresses "Mitigation of Climate Change".

This presentation will summarize the results of Working Group I emphasizing what observations tell us about climate variability and change in the past, what progress has been made in understanding the climate system, and will give a brief outlook on the projections for the remaining part of this century.